Pub Date : 2025-11-30DOI: 10.1016/j.euromechsol.2025.105971
Du Chaofan , Xu Ningning , Li Liang , Yu Chuanbin , Zhang Dingguo
This study investigates the dynamic characteristics of rotating functionally graded material (FGM) micro-beams operating in a thermal environment, incorporating size effects, A high-order coupled dynamic model is established based on the modified couple stress theory. The formulation explicitly accounts for axial shortening induced by lateral deformation (nonlinear coupling deformation term) and employs the point interpolation method (PIM) and radial point interpolation method (RPIM) to discretize the deformation field of flexible micro-beams. Lagrange's equation of the second kind provides the governing equations. The influences of critical parameters including temperature field, rotational velocity profiles, the FGM gradient index, and size dependence are quantitatively examined. The simulation results demonstrate that thermal environment and size effect exert significant, non-negligible in influences on the dynamic analysis of FGM micro-beams. Furthermore, this study confirms the efficacy of meshless methods specifically PIM and RPIM, highlighting their potential for extension to rigid-flexible-thermal coupled multi-body system dynamics.
{"title":"Dynamic analysis of a hub-FGM micro-beam based on meshless method in thermal environment","authors":"Du Chaofan , Xu Ningning , Li Liang , Yu Chuanbin , Zhang Dingguo","doi":"10.1016/j.euromechsol.2025.105971","DOIUrl":"10.1016/j.euromechsol.2025.105971","url":null,"abstract":"<div><div>This study investigates the dynamic characteristics of rotating functionally graded material (FGM) micro-beams operating in a thermal environment, incorporating size effects, A high-order coupled dynamic model is established based on the modified couple stress theory. The formulation explicitly accounts for axial shortening induced by lateral deformation (nonlinear coupling deformation term) and employs the point interpolation method (PIM) and radial point interpolation method (RPIM) to discretize the deformation field of flexible micro-beams. Lagrange's equation of the second kind provides the governing equations. The influences of critical parameters including temperature field, rotational velocity profiles, the FGM gradient index, and size dependence are quantitatively examined. The simulation results demonstrate that thermal environment and size effect exert significant, non-negligible in influences on the dynamic analysis of FGM micro-beams. Furthermore, this study confirms the efficacy of meshless methods specifically PIM and RPIM, highlighting their potential for extension to rigid-flexible-thermal coupled multi-body system dynamics.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105971"},"PeriodicalIF":4.2,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-29DOI: 10.1016/j.euromechsol.2025.105964
Esmaeal Ghavanloo , Patrizio Neff
In this paper, we consider the isotropic relaxed micromorphic model in polar coordinates and use this representation to solve explicitly an elastostatic axisymmetric extension problem involving a linear system of ordinary differential equations. To obtain an analytical solution, modified Bessel functions are utilized and closed-form solutions for the displacement and micro-distortion are obtained. We show how certain limit cases (classical linear elasticity), which are naturally included in the relaxed micromorphic model, can be efficiently achieved. Furthermore, numerical results are calculated and the effects of various parameters are examined. The results can be used to calibrate and check corresponding finite element codes.
{"title":"The isotropic relaxed micromorphic model in polar coordinates and its application to an elastostatic axisymmetric extension problem","authors":"Esmaeal Ghavanloo , Patrizio Neff","doi":"10.1016/j.euromechsol.2025.105964","DOIUrl":"10.1016/j.euromechsol.2025.105964","url":null,"abstract":"<div><div>In this paper, we consider the isotropic relaxed micromorphic model in polar coordinates and use this representation to solve explicitly an elastostatic axisymmetric extension problem involving a linear system of ordinary differential equations. To obtain an analytical solution, modified Bessel functions are utilized and closed-form solutions for the displacement and micro-distortion are obtained. We show how certain limit cases (classical linear elasticity), which are naturally included in the relaxed micromorphic model, can be efficiently achieved. Furthermore, numerical results are calculated and the effects of various parameters are examined. The results can be used to calibrate and check corresponding finite element codes.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105964"},"PeriodicalIF":4.2,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-28DOI: 10.1016/j.euromechsol.2025.105963
Julen Cortazar-Noguerol, Fernando Cortés, María Jesús Elejabarrieta
This study investigates how the sample shape factor influences the dynamic properties characterization of a silicone rubber within the linear viscoelastic regime. The effective elastic properties of elastomers are known to depend on geometry, but the effect of shape factor on the dynamic response has not been systematically characterized. To address this, cylindrical samples with varying geometries are tested under dynamic compression and torsion. The results reveal that both the complex compressive and shear moduli are affected by shape factor, and that this influence varies with frequency. To quantify the influence of shape factor and extract the material's dynamic properties, a phenomenological correction model is formulated. The model introduces frequency-dependent parameters that account for the geometric effects on the effective moduli. These corrected moduli yield a complex Poisson's ratio that exhibits a slight frequency dependence, with a decreasing real part and an increasing loss factor. This approach enables both the quantification of geometry-induced effects in dynamic mechanical testing and the extraction of intrinsic material's viscoelastic properties.
{"title":"Influence of the sample shape factor on the dynamic characterization of viscoelastic properties: complex moduli and Poisson's ratio","authors":"Julen Cortazar-Noguerol, Fernando Cortés, María Jesús Elejabarrieta","doi":"10.1016/j.euromechsol.2025.105963","DOIUrl":"10.1016/j.euromechsol.2025.105963","url":null,"abstract":"<div><div>This study investigates how the sample shape factor influences the dynamic properties characterization of a silicone rubber within the linear viscoelastic regime. The effective elastic properties of elastomers are known to depend on geometry, but the effect of shape factor on the dynamic response has not been systematically characterized. To address this, cylindrical samples with varying geometries are tested under dynamic compression and torsion. The results reveal that both the complex compressive and shear moduli are affected by shape factor, and that this influence varies with frequency. To quantify the influence of shape factor and extract the material's dynamic properties, a phenomenological correction model is formulated. The model introduces frequency-dependent parameters that account for the geometric effects on the effective moduli. These corrected moduli yield a complex Poisson's ratio that exhibits a slight frequency dependence, with a decreasing real part and an increasing loss factor. This approach enables both the quantification of geometry-induced effects in dynamic mechanical testing and the extraction of intrinsic material's viscoelastic properties.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105963"},"PeriodicalIF":4.2,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-27DOI: 10.1016/j.euromechsol.2025.105962
S. Shahab Ghafouri , M. Soltani , M.H. Momenian , O. Civalek
In this research, the free vibration behavior along with the stability analysis of two parallel three-layer sandwich beams made of porous materials and integrated with metallic face sheets inter-connected by a set of translational springs are assessed. The contemplated structure is placed on Winkler’s elastic foundation and subjected to an axial mechanical load. By considering the effects of shear deformation within the framework of Timoshenko beam model, and using the method of calculus of variations and Hamilton’s principle, the system of governing motion equations of the corresponding structure is obtained and analytically solved via Navier’s method and Fourier series functions for simply supported boundary conditions. The dispersion of internal pores is considered based on three different patterns through the thickness of the beam and its effect on the natural frequencies and endurable buckling loads of the under-investigation model is precisely investigated. Also, the impact of the changes in the porosity coefficient, aspect ratio, thickness ratio, and stiffness of elastic medium is comprehensively explored. Furthermore, the effect of tensile and/or compressive axial preloading on the natural frequencies of the contemplated double-bonded system is perused in detail. The obtained results indicate that changes in theses parameters have a remarkable influence on the stability and vibration performance of the system, and by considering appropriate design quantities, it is possible to attain the desired buckling capacity and vibrational characteristics, while minimizing the weight of the structure.
{"title":"Impact of axial preloading on the vibrational response of a double FG porous sandwich beam system surrounded by elastic medium","authors":"S. Shahab Ghafouri , M. Soltani , M.H. Momenian , O. Civalek","doi":"10.1016/j.euromechsol.2025.105962","DOIUrl":"10.1016/j.euromechsol.2025.105962","url":null,"abstract":"<div><div>In this research, the free vibration behavior along with the stability analysis of two parallel three-layer sandwich beams made of porous materials and integrated with metallic face sheets inter-connected by a set of translational springs are assessed. The contemplated structure is placed on Winkler’s elastic foundation and subjected to an axial mechanical load. By considering the effects of shear deformation within the framework of Timoshenko beam model, and using the method of calculus of variations and Hamilton’s principle, the system of governing motion equations of the corresponding structure is obtained and analytically solved via Navier’s method and Fourier series functions for simply supported boundary conditions. The dispersion of internal pores is considered based on three different patterns through the thickness of the beam and its effect on the natural frequencies and endurable buckling loads of the under-investigation model is precisely investigated. Also, the impact of the changes in the porosity coefficient, aspect ratio, thickness ratio, and stiffness of elastic medium is comprehensively explored. Furthermore, the effect of tensile and/or compressive axial preloading on the natural frequencies of the contemplated double-bonded system is perused in detail. The obtained results indicate that changes in theses parameters have a remarkable influence on the stability and vibration performance of the system, and by considering appropriate design quantities, it is possible to attain the desired buckling capacity and vibrational characteristics, while minimizing the weight of the structure.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105962"},"PeriodicalIF":4.2,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-26DOI: 10.1016/j.euromechsol.2025.105961
Hadi Arvin , Maryam Shahriari-kahkeshi , Hossein Ghahhari , Ömer Civalek
In this study, an adaptive fuzzy sliding mode controller is proposed to mitigate the vibrations of a hysteretic sandwiched piezoelectric nanocomposite beam regarding system uncertainties, accounting for the intrinsic hysteresis behavior of the actuator layer. The core consists of a graphene sheet-reinforced composite, while the piezoelectric facesheets operate as both sensors and actuators. The actuator's hysteresis is modeled using a Bouc-Wen formulation with uncertain parameters. To compensate for this uncertain nonlinearity and suppress vibrations, an adaptive fuzzy sliding mode controller is developed, with stability guaranteed via Lyapunov's direct method. The results demonstrate the controller's high effectiveness in mitigating mechanical vibrations. The robustness of the proposed controller against parameter uncertainties allows it to manage small variations in structural stiffness and mass resulting from changes in the distribution pattern of the nanocomposite and the piezoelectric thickness ratio. As a result, the controlled deflection of the nanocomposite beam remains unaffected by these two parameters. The most important parameter affecting the controlled response is the type of boundary condition. Decreasing the piezoelectric layer thickness enhances the controller's effort. Due to the hysteresis behavior of the actuator, a steady-state controller effort remains in the system, which is more pronounced for the clamped-clamped nanocomposite beam. The corresponding hysteretic loop shows a similar observation for this boundary condition.
{"title":"Vibration mitigation in piezoelectric sandwiched nanocomposite beam-like structures considering Bouc-Wen hysteresis: An adaptive fuzzy sliding mode control approach","authors":"Hadi Arvin , Maryam Shahriari-kahkeshi , Hossein Ghahhari , Ömer Civalek","doi":"10.1016/j.euromechsol.2025.105961","DOIUrl":"10.1016/j.euromechsol.2025.105961","url":null,"abstract":"<div><div>In this study, an adaptive fuzzy sliding mode controller is proposed to mitigate the vibrations of a hysteretic sandwiched piezoelectric nanocomposite beam regarding system uncertainties, accounting for the intrinsic hysteresis behavior of the actuator layer. The core consists of a graphene sheet-reinforced composite, while the piezoelectric facesheets operate as both sensors and actuators. The actuator's hysteresis is modeled using a Bouc-Wen formulation with uncertain parameters. To compensate for this uncertain nonlinearity and suppress vibrations, an adaptive fuzzy sliding mode controller is developed, with stability guaranteed via Lyapunov's direct method. The results demonstrate the controller's high effectiveness in mitigating mechanical vibrations. The robustness of the proposed controller against parameter uncertainties allows it to manage small variations in structural stiffness and mass resulting from changes in the distribution pattern of the nanocomposite and the piezoelectric thickness ratio. As a result, the controlled deflection of the nanocomposite beam remains unaffected by these two parameters. The most important parameter affecting the controlled response is the type of boundary condition. Decreasing the piezoelectric layer thickness enhances the controller's effort. Due to the hysteresis behavior of the actuator, a steady-state controller effort remains in the system, which is more pronounced for the clamped-clamped nanocomposite beam. The corresponding hysteretic loop shows a similar observation for this boundary condition.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105961"},"PeriodicalIF":4.2,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-26DOI: 10.1016/j.euromechsol.2025.105960
Susmita Panda , Arnab Banerjee , Bappaditya Manna
The heavier axle moving at high speed over critical locations such as road or rail crossings may induce excessive vibrations, detrimental to structure and passenger comfort. To address this, vibration absorbers can be tuned to effectively reduce the vibrations caused by moving wheel loads. Traditional tuned mass systems and inerter-based devices often face limitations due to requirement of heavy mass and moving components. To overcome these challenges, this paper introduces a theoretical formulation for novel negative-stiffness inertial amplifier-based vibration absorber system (NSIABVA) to mitigate train-induced vibrations. To analyze a simply-supported bridge’s dynamics, an Euler–Bernoulli beam under successive loads is modeled using a non-dimensional framework. Additionally, optimization of NSIABVA using a genetic algorithm is proposed and shows strong agreement with Den Hartog’s classical theory for tuned mass systems, validating its accuracy. The proposed NSIABVA configuration offers superior vibration mitigation driven by significant effective mass and stiffness amplification for different values of frequency and mass tuning ratio. While conventional IABVAs reduce displacement by 50%–70%, the NSIABVA achieves a 70%–90% reduction. Unlike IABVA, which mainly enhances energy dissipation, NSIABVA also improves damping and structural load-bearing capacity. Additionally, statistical analysis identifies optimal absorber design parameters across diverse loading and bridge conditions, enhancing the system’s applicability.
{"title":"A novel negative stiffness inertial amplifier absorber for mitigating bridge vibrations under moving loads","authors":"Susmita Panda , Arnab Banerjee , Bappaditya Manna","doi":"10.1016/j.euromechsol.2025.105960","DOIUrl":"10.1016/j.euromechsol.2025.105960","url":null,"abstract":"<div><div>The heavier axle moving at high speed over critical locations such as road or rail crossings may induce excessive vibrations, detrimental to structure and passenger comfort. To address this, vibration absorbers can be tuned to effectively reduce the vibrations caused by moving wheel loads. Traditional tuned mass systems and inerter-based devices often face limitations due to requirement of heavy mass and moving components. To overcome these challenges, this paper introduces a theoretical formulation for novel negative-stiffness inertial amplifier-based vibration absorber system (NSIABVA) to mitigate train-induced vibrations. To analyze a simply-supported bridge’s dynamics, an Euler–Bernoulli beam under successive loads is modeled using a non-dimensional framework. Additionally, optimization of NSIABVA using a genetic algorithm is proposed and shows strong agreement with Den Hartog’s classical theory for tuned mass systems, validating its accuracy. The proposed NSIABVA configuration offers superior vibration mitigation driven by significant effective mass and stiffness amplification for different values of frequency and mass tuning ratio. While conventional IABVAs reduce displacement by 50%–70%, the NSIABVA achieves a 70%–90% reduction. Unlike IABVA, which mainly enhances energy dissipation, NSIABVA also improves damping and structural load-bearing capacity. Additionally, statistical analysis identifies optimal absorber design parameters across diverse loading and bridge conditions, enhancing the system’s applicability.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"116 ","pages":"Article 105960"},"PeriodicalIF":4.2,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We propose an asymptotic method for homogenizing periodic elastic lattices that works in the presence of mechanisms, both of the macroscopic type (strain-producing modes) and of the microscopic type (internal modes). When a microscopic mechanism is present, the unit-cell problem produced by classical homogenization is singular. It can be fixed by including the amplitude of the mechanism as an additional macroscopic degree of freedom (enrichment variable) contributing to the effective energy via its gradient . When a macroscopic mechanism is present, homogenization delivers a degenerate effective energy at leading order, which can be regularized by accounting for the strain gradient. We introduce an asymptotic second-order homogenization scheme that integrates these two features: it delivers an effective energy capturing both the strain-gradient effect relevant to macroscopic mechanisms, and the regularization relevant to microscopic mechanisms, if any is present. The versatility of the approach is illustrated with a selection of lattices displaying a variety of effective behaviors. It follows a unified pattern that leads to a classification of these effective behaviors. Whereas the procedure delivers known effective models for elastic lattices without mechanisms, it can generate novel effective models for lattices possessing mechanisms.
{"title":"Homogenizing elastic lattices with mechanisms","authors":"Basile Audoly , Claire Lestringant , Hussein Nassar","doi":"10.1016/j.euromechsol.2025.105956","DOIUrl":"10.1016/j.euromechsol.2025.105956","url":null,"abstract":"<div><div>We propose an asymptotic method for homogenizing periodic elastic lattices that works in the presence of mechanisms, both of the macroscopic type (strain-producing modes) and of the microscopic type (internal modes). When a microscopic mechanism is present, the unit-cell problem produced by classical homogenization is singular. It can be fixed by including the amplitude <span><math><mrow><mi>θ</mi><mrow><mo>(</mo><mi>X</mi><mo>)</mo></mrow></mrow></math></span> of the mechanism as an additional macroscopic degree of freedom (enrichment variable) contributing to the effective energy via its gradient <span><math><mrow><mo>∇</mo><mi>θ</mi><mrow><mo>(</mo><mi>X</mi><mo>)</mo></mrow></mrow></math></span>. When a macroscopic mechanism is present, homogenization delivers a degenerate effective energy at leading order, which can be regularized by accounting for the strain gradient. We introduce an asymptotic second-order homogenization scheme that integrates these two features: it delivers an effective energy capturing both the strain-gradient effect <span><math><mrow><mo>∇</mo><mi>ɛ</mi><mrow><mo>(</mo><mi>X</mi><mo>)</mo></mrow></mrow></math></span> relevant to macroscopic mechanisms, and the <span><math><mrow><mo>∇</mo><mi>θ</mi><mrow><mo>(</mo><mi>X</mi><mo>)</mo></mrow></mrow></math></span> regularization relevant to microscopic mechanisms, if any is present. The versatility of the approach is illustrated with a selection of lattices displaying a variety of effective behaviors. It follows a unified pattern that leads to a classification of these effective behaviors. Whereas the procedure delivers known effective models for elastic lattices without mechanisms, it can generate novel effective models for lattices possessing mechanisms.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105956"},"PeriodicalIF":4.2,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1016/j.euromechsol.2025.105959
Shuo Liu , Kaifa Wang , Guigen Wang , Baolin Wang , Tinh Quoc Bui
As the spacecraft enters and maneuvers within its celestial orbit, the photovoltaic structures inevitably experience severe dynamic loading. It is imperative to investigate the dynamic mechanical properties in space structure design, as this is a crucial metric for evaluating the capability against impulsive loads. This study embeds isogeometric analysis (IGA) within a non-classical refined shear deformation theory (RSDT) incorporating the modified couple stress theory (MCST) to capture size-dependent geometrically nonlinear dynamics of organic solar cells (OSCs). Various parameters such as boundary conditions, damping, and loading types are considered. Numerical results confirm convergence and accuracy against established benchmarks. Results demonstrate that the size effects significantly enhance stiffness and reduce deflection. The geometrically nonlinear model lowers vibration amplitudes and prolongs periods. Considering damping, the energy system has been effectively dissipated. In addition, safety verification confirms that ITO (indium tin oxide) layer strains remain below critical thresholds under extreme loads. A semi-empirical formula is established, enabling direct estimation of the allowable dynamic load before brittle failure.
{"title":"Geometrically nonlinear dynamic analysis of multilayered organic solar cells with a non-classical plate theory and isogeometric anlysis","authors":"Shuo Liu , Kaifa Wang , Guigen Wang , Baolin Wang , Tinh Quoc Bui","doi":"10.1016/j.euromechsol.2025.105959","DOIUrl":"10.1016/j.euromechsol.2025.105959","url":null,"abstract":"<div><div>As the spacecraft enters and maneuvers within its celestial orbit, the photovoltaic structures inevitably experience severe dynamic loading. It is imperative to investigate the dynamic mechanical properties in space structure design, as this is a crucial metric for evaluating the capability against impulsive loads. This study embeds isogeometric analysis (IGA) within a non-classical refined shear deformation theory (RSDT) incorporating the modified couple stress theory (MCST) to capture size-dependent geometrically nonlinear dynamics of organic solar cells (OSCs). Various parameters such as boundary conditions, damping, and loading types are considered. Numerical results confirm convergence and accuracy against established benchmarks. Results demonstrate that the size effects significantly enhance stiffness and reduce deflection. The geometrically nonlinear model lowers vibration amplitudes and prolongs periods. Considering damping, the energy system has been effectively dissipated. In addition, safety verification confirms that ITO (indium tin oxide) layer strains remain below critical thresholds under extreme loads. A semi-empirical formula is established, enabling direct estimation of the allowable dynamic load before brittle failure.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"116 ","pages":"Article 105959"},"PeriodicalIF":4.2,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1016/j.euromechsol.2025.105953
Chong Gao , Yihui Huang , Qian Sun , Bo Cao , Takeshi Iwamoto , Tsutomu Umeda , Takayuki Kusaka
Past experimental result reveals that a region of the fracture initiation in metastable austenitic stainless steel SUS 304 during a small punch test changes from the loading side to free surface with respect to the loading rate. Since a measurement of a time series of the martensite and temperature distribution, which strongly affects the fracture behavior, is difficult to be realized during testing, a precise finite element (FE) analysis is necessary to support further discussions on the mechanism of the loading rate sensitivity. In the current work, the phenomena observed in the tests are precisely reproduced through the FE analyses including the martensitic transformation and the damage evolution modelled by authors. The condition for the onset of crack extension is provided to assist the future works in determining where the initiation occurs. Even though the austenitic phase is dominant for the fracture, a larger damage variable appears in the region where a significant quantity of martensite is distributed. Simultaneously, the work clarifies the influence of reducing the amount of martensite with respect to the loading rate on ductility of the material. In the dynamic loading, it is newly discovered that the thermal softening plays an important role, inducing the fracture from the free surface of the specimen.
{"title":"Fracture mechanism in SUS304 during small punch tests","authors":"Chong Gao , Yihui Huang , Qian Sun , Bo Cao , Takeshi Iwamoto , Tsutomu Umeda , Takayuki Kusaka","doi":"10.1016/j.euromechsol.2025.105953","DOIUrl":"10.1016/j.euromechsol.2025.105953","url":null,"abstract":"<div><div>Past experimental result reveals that a region of the fracture initiation in metastable austenitic stainless steel SUS 304 during a small punch test changes from the loading side to free surface with respect to the loading rate. Since a measurement of a time series of the martensite and temperature distribution, which strongly affects the fracture behavior, is difficult to be realized during testing, a precise finite element (FE) analysis is necessary to support further discussions on the mechanism of the loading rate sensitivity. In the current work, the phenomena observed in the tests are precisely reproduced through the FE analyses including the martensitic transformation and the damage evolution modelled by authors. The condition for the onset of crack extension is provided to assist the future works in determining where the initiation occurs. Even though the austenitic phase is dominant for the fracture, a larger damage variable appears in the region where a significant quantity of martensite is distributed. Simultaneously, the work clarifies the influence of reducing the amount of martensite with respect to the loading rate on ductility of the material. In the dynamic loading, it is newly discovered that the thermal softening plays an important role, inducing the fracture from the free surface of the specimen.</div></div>","PeriodicalId":50483,"journal":{"name":"European Journal of Mechanics A-Solids","volume":"117 ","pages":"Article 105953"},"PeriodicalIF":4.2,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1016/j.euromechsol.2025.105951
Yifang Qin , Shunhua Chen , Mitsuteru Asai
The main purpose of this work is to develop a nodal-based Lagrange multiplier/cohesive zone (LM/CZ) approach for accurate simulations of internal-interfacial crack interactions in laminated structures. The appeal of the presented approach lies in dealing with crack interactions in a natural and simple way, while inheriting the advantages of addressing the so-called artificial compliance issue and allowing for the use of non-matching meshes between structure layers. To achieve the end, the developed approach introduces the LM method to accurately enforce the continuity across nodes, and adopts a shifted traction separation law (TSL) to govern the subsequent cohesive crack behaviors. Internal and interfacial nodal groups are constructed, and the concept of ghost points is introduced to facilitate interfacial crack simulations with both matching and non-matching meshes in a unified way. Special attention is given to crack message transmission to effectively account for internal-interfacial crack interactions. The accuracy and effectiveness of the developed approach are demonstrated via benchmark examples. Finally, the capacity of the presented approach is further explored by extending the applications to crack interactions of two- and three-fiber/matrix units. Results show that our approach can effectively simulate complex crack interactions, including internal crack-induced interfacial crack as well as interfacial debonding triggered by internal cracks.
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